The invention is directed to a fuel injection pump for fuel injection combustion engines.
In a known fuel injection pump of this type (German Offenlegungsschrift No. 3,004,460), optimization of injection is achieved by controlling the pressure in a pressure reservoir. The hydraulic fluid available from this pressure reservoir serves the controlled actuation of a pump piston that delivers a previously stored quantity of fuel for injection. The reservoir is embodied as a constant volume reservoir, thus having the disadvantage that only a small amount of fuel can be taken from the feed space of the high pressure pump without a noticeable loss of pressure.
This known fuel injection pump is very complex in respect of its control over the quantity of fuel to be injected and in respect of its control over the actuating force for the injection, inasmuch as it requires, in addition to a electrically controlled dosing valve and an electrically controlled adjustment for the quantity of fuel to be delivered, a mechanically controlled valve arrangement for distributing the quantity of fuel to be injected to the various injection points (a distributor injection pump).
Control of the start of injection is disadvantageously controlled by the leading edges of a pump piston and distributor piston and thus permits only a narrow range of control within the limits imposed by the pump piston stroke drive or within the adjustment range available from the pump piston cam drive, respectively.